Experimental Study on the Stability of a Novel Nanocomposite-Enhanced Viscoelastic Surfactant Solution as a Fracturing Fluid under Unconventional Reservoir Stimulation

Abstract

Fe3O4@ZnO nanocomposites (NCs) were synthesized to improve the stability of the wormlike micelle (WLM) network structure of viscoelastic surfactant (VES) fracturing fluid and were characterized by Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Then, an NC-enhanced viscoelastic surfactant solution as a fracturing fluid (NC-VES) was prepared, and its properties, including settlement stability, interactions between NCs and WLMs, proppant-transporting performance and gel-breaking properties, were systematically studied. More importantly, the influences of the NC concentration, shear rate, temperature and pH level on the stability of NC-VES were systematically investigated. The experimental results show that the NC-VES with a suitable content of NCs (0.1 wt.%) shows superior stability at 95 °C or at a high shear rate. Meanwhile, the NC-VES has an acceptable wide pH stability range of 6–9. In addition, the NC-VES possesses good sand-carrying performance and gel-breaking properties, while the NCs can be easily separated and recycled by applying a magnetic field. The temperature-resistant, stable and environmentally friendly fracturing fluid opens an opportunity for the future hydraulic fracturing of unconventional reservoirs.

Review on High-Temperature-Resistant Viscoelastic Surfactant Fracturing Fluids: State-of-the-Art and Perspectives

“…and organic salts such as salicylate, tosylate, or dichlorobenzoate, etc. are the most commonly used VES systems. ,, The typical examples are cetyltrimethylammonium bromide (CTAB), − octadecyl trimethylammonium chloride (OTAC), and cetyltrimethylammonium tosylate (CTAT). , Besides, there are other cationic surfactant systems, such as N -cetyl- N , N -di­(2-hydroxyethyl)­methylammonium bromide (CHEMAB), oleyl methyl bis­(2-hydroxyethyl)­ammonium chloride (OMHAC), and 2-hydroxyethyl dimethyl hexadecyl ammonium acetate (HDMHA) . As illustrated in Figure , the cationic surfactants mentioned above are short-tail (≤C18) surfactants.…”

“…Schematic diagram of the stability for the WLM networks’ structure reinforced by the pyroelectric nanoparticles at high temperatures. Reproduced with permission from ref . Copyright 2022 Multidisciplinary Digital Publishing Institute (MDPI).…”

“…From the cost perspective, nanosilica is a preferred nanomaterial to enhance the performances of the VES fluids. The diversification of nanomaterial resources (such as nanomaterials with magnetic or pyroelectric effects) and the optimization of the production process are effective ways to reduce costs. For example, in the reservoir, iron oxide NPs with magnetic susceptibility can be used as nanosensors to improve downhole information.…”

Review on Enhancing Rheological Characteristics of Viscoelastic Surfactant Fracturing Fluids by Nanoparticles: Advances, Challenges, and Perspectives

“…This degradation weakens their performance as clean fracturing fluids. To address this, some effective methods are needed to reinforce or stabilize the network structure of VESFFs in harsh reservoir conditions to maintain their viscoelasticity and expand their use in challenging reservoir conditions. , Nanoparticles have been found to have a beneficial role in VES fluid systems by strengthening the micelle–micelle interactions. They enhance viscosity at high temperatures and reduce fluid leak off rates.…”

Metal Oxide Nanomaterials: From Fundamentals to Applications

“…Other fascinating properties of nanocomposite based on metal oxides nanoparticles, particularly from ZnO, were explored by several other research groups [ 6 ]. For example, Si et al synthesized Fe 3 O 4 @ZnO nanocomposites (NCs) to improve the stability of the viscoelastic surfactant (VES) fracturing fluid [ 7 ]. At a loading of 0.1 wt.%, this NC-VES nanocomposite showed superior stability at 95 °C or at a high shear rate and good sand-carrying performance and gel-breaking properties.…”